Safety valve apparatus for rotary drilling equipment

ABSTRACT

A device for automatically controlling drilling rig prime mover power transmission to the rotary table upon sensing of an excessive torque encountered by the drill string. The device consists of a plurality of valves interconnected in bypass of normal neutral brake and master clutch activation mechanism which can be energized to assume full automatic command of the rotary table and drive thereto such that sensing of excessive torque actuates the safety valve device to energize the neutral brake and de-energize the master clutch supplying rotary drive power to the rotary table. Thereafter, lessening of the excessive torque will automatically enable reactivation of the master clutch and neutral brake to resume application of drive power to the rotary table.

United States Patent [191 Kenney SAFETY VALVE APPARATUS FOR ROTARY DRILLING EQUIPMENT [76] Inventor: Lindel D. Kenney, 53 Tropicana Ave., Odessa, Tex. 79762 [22] Filed: Sept. 20, 1974 211 App]. No.2 507,928

[ 51 Sept. 16, 1975 [57] ABSTRACT A device for automatically controlling drilling rig prime mover power transmission to the rotary table upon sensing of an excessive torque encountered by the drill string, The device consists of a plurality of valves interconnected in bypass of normal neutral brake and master clutch activation mechanism which can be energized to assume full automatic command 52 US. Cl 173 12; 73 136 R; 192 12 C is 1} 1m. cm E2lB 3/06 0f the Mary table and drive berm Such Sensing [58] Field of Search n 173/12 8 73/136 of excessive torque actuates the safety valve device to b h C 03 energize the neutral brake and de-energize the master clutch supplying rotary drive power to the rotary ta- [56] References Cited ble. Thereafter, lessening of the excessive torque will automatically enable reactivation of the master clutch UNITED STATES PATENTS and neutral brake to resume application of drive 2,279,597 4 1942 Selmer 1. 192 12 0 power to the rotary table 2,634,099 4/1953 OLeary 173/9 2,700,302 l/l955 Decker 73/136 R Primary Examiner-Ernest R. Purser Claims, 7 Drawing Figures Attorney, Agent, or FirmRobert M. Hessin Y /0 /4 M ,/2 ,/a PP/ME- MASTER A/E .1 7 P0742 Y MOVEE aura/1 .BE/IKE '*T mam FLU/0 f8 A VA L V5 PPfi'Sl/EE colt/rem ggkgue Sal/F65 U,(// 26 g N 01? SAFETY VALVE APPARATUS FOR ROTARY DRILLING EQUIPMENT BACKGROUND OF THE INVENTION 1. Field of the Invention 1 The invention relates generally to rotary drilling rig safety apparatus and, more particularly, but not by way of limitation, it relates to an improved safety valve device for anticipating and guarding against application of excessive torque to the drill string and thus avoiding twist-off of the drill string during drilling operations 2. Description of the Prior Art The prior art includes various types of safety apparatus for use in and around rotary drilling equipment but there is apparently little or no apparatus of the type which functions to automatically sense excessive drill string torque via rotary table power sensing thereafter to effect complete prime mover power shutdown to avoid twist-off of the drill string. The time-honored reliance has been for the drilling operator to maintain constant surveillance of his various gauges and record charts on the drilling platform and to manually control rotary table speed of rotation and power application. Various recording mechanisms are now utilized on the drilling platform, and such mechanisms include numerous alarm devices and safety cutoff features dealing with varied facets of the drilling operation; however, the effective cessation of prime mover power application to the rotary table by relatively inexpensive and fully automatic means has not been achieved heretofore to this inventors knowledge.

SUMMARY OF THE INVENTION The present invention contemplates a safety valve device which is interposed in the normal operating energization circuits of the neutral brake and master clutch mechanism of the rig prime mover. The torque of the rotary table is continually sensed and indication is transmitted to the safety valve device which, when the torque exceeds a predetermined adjustable limit, actuates the valve combination such that the neutral brake and then the master clutch are actuated to cease power transmission to the rotary table.

Therefore, it is an object of the present invention to provide a safety valve device which effectively prevents application of excessive torque sufficient to cause twist-off in the drill string.

It is also an object of the invention to provide a device which is relatively simple and inexpensive yet which functions to enable great savings in equipment and manpower costs during drilling operations.

It is still another object of the present invention to provide a safety valve device which can be interconnected into the rotary drilling rig power works without interfering with normal drilling techniques and control measures when in its de-energized state.

Finally, it is an object of the present invention to provide a safety valve device for preventing twist-off which may be readily set for response to a selected rotary torque value as may be determined from such factors as depth of operation, speed of drilling, strata density and the like.

Othr objects andzadvantages of the invention will be evident from the following detailed description when read in conjunction with the. accompanying drawings which illustrate the invention-.- ;v

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of the essential drive elements of a rotary drilling rig as interconnected with the present invention;

FIG. 2 is a side elevation of one form of torque sensor device which may be employed in the present invention;

FIG. 3 is a schematic diagram of a safety valve device constructed in accordance with the present invention;

FIG. 4 is a schematic illustration of one form of torque actuation switch which may be utilized in the present invention;

FIG, 5 is a flow diagram of the safety valve device when in the de-energized operative condition;

FIG. 6 is a flow diagram of the safety valve device when in the normal operating energized condition; and

FIG. 7 is a flow diagram of the safety valve device when actuated in response to the rotary table excessive torque condition.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1, the block diagram illustrates the interconnection of rig components and the rotary table torque control scheme. A prime mover 10 provides basic power for energizing the various components of the drilling rig in well-known manner. The prime mover 10 may be any of the various conventional types such as diesel engine, diesel electric, steam or the like; however, diesel engines have evolved to be most often utilized in todays drilling technology due toversatility and economy considerations..More often than not several diesel engines are utilizedin parallel providing rotary drive output via a mechanical linkage 12 through a master clutch 14 and neutral brake 16 for application via power transmission linkage 18 to the rig draw works (not shown) and rotary table 20.

The power transmission linkage 18 is usually comprised of a series of V-belt or roller chain linkages serving to deliver the rotary power to the draw works and via branch mechanical linkage to the rotary table 20. Rotary table 20, which, of course, provides rotation to the drill string (not shown), in more conventional apparatus consists of a simple chain and sprocket interconnection supplying rotary drive to the rotary table 20. The master clutch l4 and neutral brake 16 are suitably interposed between the rotary drive output of prime mover l0 and the power transmission linkage 18 to provide a singular means for basic drive control to the entire rig powering system, i.e. draw works, rotary table and ancillary power equipment. There are various types of master clutch 14 and neutral brake l6 utilized in the technology and any of such well-known commercially available types may be utilized with the present invention.

A power take-off linkage 22 from main power transmission linkage 18 applies rotational input to a torque sensor 24 which, in turn, provides indication input via line 26 to a valve control unit 28. The valve control unit 28, as controlled by input from torque sensor 24, controls actuation of master clutch l4 and neutral brake 16 via connecting lines 30 and 32. Control lines 30 and 32 may consist of fluid pressure lines, either hydraulic or pneumatic, depending upon selection of master clutch 14 and neutral brake 16, which control application of the fluid pressure from an associated fluid pressure source 34 under control of the valve control unit 28.

FIG. 2 illustrates torque sensor 24 which is a torque gauging unit functioning in response to tension in a drive chain 36 (linkage 22) which supplies rotary drive to the rotary table 20. Thus, rotary table drive is connected from power transmission linkage 18 by means of a sprocket 38 which motion is transmitted by a roller chain 36 to an input sprocket 40 providing direct rotational input to the rotary table in well-known manner. Drive tension is gauged by sensing the amount of slack allowed in the lower or return side of roller chain 36. An idler sprocket 42 is movably mounted on a suitable bracket 44 beneath roller chain 36, and idler sprocket wheel 46 is continually urged upward against roller chain 36 by means of a hydraulic cylinder 48. The hydraulic cylinder 48 includes output line 26 conducting fluid pressure differential in response to the amount of tension of roller chain 36 bearing downward against sensing wheel 46. Thus, with any increase of rotary table torque as reflected back through input sprocket 40, increased tension is placed on the underside of roller chain 36 which depresses the idler sprocket 42 such that fluid pressure increase is transmitted via line 26 for indication and control of valve control unit 28, as will be further described below.

The valve control unit 28 is shown in greater detail in FIG. 3. The valve control unit 28 is not of large size and may be constructed in a suitable chassis for removable installation at the oil field drilling site. Valve control unit 28 need only be supplied with a suitable source of A-C power 50 with direct control of power application by means of an on-off switch 52 to power energization lines 54. The A-C power energization line 54 is applied to each of two-way valves 56, 58 and 60 as well as to a three-way valve 62. Each of the two-way valves 56-60 and three-way valve 62 are well-known and commercially available forms of solenoid operated fluid pressure switching valves. For example, the normally closed valves 56 and 60 (two-way) may be ASCO Model 8262C22, the normally open two-way valve 58 may be an ASCO Model 8262C34, and the three-way valve 62 may be an ASCO Model 83006l(U) type. A four-way valve 64 is solenoid connected via energizing lead 66 through a torque sensor switch 68 (to be further described) to conduct energizing power from A-C lead 54. The four-way valve 64 may be any of various commercially available types, e.g. the ASCO Model 834470.

The various valve units in the illustration of FIG. 3 are shown in the normal or de-energized position. Thus, a brake control fuild line 70 is connected to a normal open port of two-way valve 58 with through connection to a brake line 72 which is also connected to a normal closed port of two-way valve 56 via parallel fluid line 74. The opposite side of normal closed port of two-way valve 56 is then connected via fluid line 76 through a normal open port of four-way valve 64 for return via exhaust line 78.

A clutch control fluid line 80 is connected through a normal open port of three-way valve 62 and further conduction via a fluid line 82 for return via clutch fluid line 84 and input to the normally open port of two-way valve 60. The through connection of the normally closed port of two-way valve 60 is then connected via fluid line 86 through a normally open port of four-way valve 64 with through connection to a fluid line 88 to a normally open port of three-way valve 62.

The torque sensor switch 68 is responsive to increased pressure via fluid pressure line 26 from the torque sensor 24 (FIG. 2), and it functions to complete application of A-C power from lead 54 to lead 66 with solenoid activation of four-way valve 64 upon sensing greater than a pre-set torque quantity. While any of various pressure responsive electrical switches may be utilized in the present invention, field testing has been carried out utilizing a gauge/switch type of assembly as shown in FIG. 4.

Thus, FIG. 4 consists of a conventional form of pressure responsive gauge, e.g. the Bourdon tube type of gauge structure, which receives fluid pressure input via fluid line 26 to provide proportional gauge indication via indicator needle 90 moving relative to calibrated graduation markings 92. In order to provide the requisite electrical switching function, a normally open microswitch 94 having an actuator 96 is disposed on a slidable shoulder support 98 which is releasably secured by means of a screw tab 100. Thus, release of screw tab 100 allows rotation of support shoulder 98 and microswitch 94 to any desired setting about the graduation marking 92, such setting to be determined from the drillers information relative to substratum, drilling speed and other related data. The microswitch 94 is normally open and applies the power side of the A-C line to actuate the four-way valve 64 (FIG. 3) by connecting electrical leads 54 and 66 when indicator needle 90 reaches the selected torque limit and depresses switch actuator 96.

In operation, utilization of the valve control unit 28 has the advantage that it can be interconnected into the drive system as shown in FIG. 1, and if de-energized by leaving switch 52 open the system will function in normal manner under complete control of the driller and rig platform surveillance. Then, upon actuation of control switch 52 (FIG. 3), the valve control unit 28 will assume automatic control of the power application to rotary table 20 (FIG. 1) to cease application of rotary power upon sensing of high or dangerous torque levels; thereafter, upon reduction of the excessive rotary table torque requirement, valve control unit 28 will once again actuate to engage the master clutch l4 and release neutral brake 16 so that rotary drilling will again proceed automatically.

The flow illustration of FIG. 5 illustrates the condition of valve control unit 28 when in the de-energized condition, i.e. with power switch 52 open, and the rotary drilling rig functioning in normal manner. Thus, the pressure application pattern of the flow diagram of FIG. 5 is the same as that previously described in the schematic diagram of FIG. 3. Clutch control fluid line 80 and clutch fluid line 84 are return connected so that clutch control may be effected at a different location, e.g. probably at the drillers rig platform location. Similarly, brake control fluid line 70 and brake line 72 are return connected for similar operational control.

The flow diagram of FIG. 6 illustrates the pressure distribution when control switch 52 (FIG. 3) is connected to its ON position and each of two-way valves 56, 58 and 60 and three-way valve 62 are solenoid activated to alternative spool positions. In this activated condition, valve control unit 28 allows rotary drilling function but is subject to automatic cut-off control in response to torque sensor switch 68 (FIG. 3). Thus,

pressure distribution from brake fluid line 72 proceeds via fluid line 74 through an alternate open port of twoway valve 56 with return along fluid line 76 and deenergized four-way valve 64 for return via the exhaust fluid line 78. The master clutch 14 is then controlled by fluid distribution along fluid line 80 and the alternate port of three-way valve 62 for conduction via fluid line 88 and a normal port of four-way valve 64 with return via fluid line 86 and an alternate port of two-way valve 60 such that final pressure return is through clutch fluid line 84. Control of the master clutch 14 and neutral brake 16 is still possible from a remote position or the drillers control console, but application of rotary power to rotary table is now subject to automatic cut-off, as will be further described below.

Referring now to the flow diagram of FIG. 7, encounter of an over-torque condition causes actuation of torque sensor switch 68 (FIG. 3) to energize the solenoid of four-way valve 64 such that pressure conduction therethrough is reversed and fluid pressure is applied to actuate neutral brake l6 and master clutch 14. Thus, master clutch 14 is released with pressure reversal at fluid line 84 through two-way valve 60, fluid line 86, and an alternative port of four-way valve 64 to exhaust fluid line 78. Simultaneously, neutral brake 16 is actuated with application of fluid pressure on brake fluid line 72 as derived from a pressure source input at clutch control fluid line 80, ported through three-way valve 62 and an alternative port of four-way valve 64 via fluid line 76 and two-way valve 56 to the brake fluid line 72.

The foregoing discloses a novel valve control device of reliable and economical construction which affords the advantages of avoiding twist-off of drill string through automatic rotary torque control. The device has the several advantages of being able to be connected into the normal rig power and draw works structure while allowing the options of normal driller surveillance operation or complete automatic torque sensitive operation, depending upon the exigencies of the particular operation. It should be understood that while particular structure has been described for such functions as rotary drive torque sensing, there are various devices susceptible of inclusion in the present teachings, i.e. electrical pneumatic or hydraulic sensing and transmission devices, any of which will function to provide the necessary over-torque signal for actuation of valve control unit 28 with stoppage of rotary table drive.

Changes may be made in the combination and arrangement of elements as heretofore set forth in the specification and shown in the drawings; it being understood that changes may be made in the embodiments disclosed without departing from the spirit and scope of the invention as defined in the following claims.

What is claimed is:

l. A control device for automated control of fluid pressure actuated master clutch and neutral brake which transmit primary power for operation of a well drillingrotary table, comprising:

first valve means actuated to port fluid pressure from said brake to a first output fluid line;

second valve means actuated to port fluid pressure from an input fluid line to said clutch;

three-way valve means actuated to port fluid pressure from a fluid pressure source to a second output fluid line; and

four-way valve means normally connecting said second output fluid line to said input fluid line to said second valve means while connecting said first output fluid line to a pressure exhaust line, said fourway valve means being actuatable to alternate porting connections whereby said input fluid line is connected to said pressure exhaust line to release the master clutch and said second output fluid is connected to said first output fluid line through said first valve means to actuate. the neutral brake.

2. A control device as set forth in claim 1 which is further characterized to include:

third normally open valve means interconnected in said first output fluid line and actuated to port fluid pressure simultaneous with actuation of said first and second valve means.

3. A control device as set forth in claim 1 which is further characterized to include:

means for sensing the amount of torque applied to said rotary table and providing a proportional output indication; and

means responsive to a pre-selected maximum of said output indication to actuate said four-way valve means.

4. A control device as set forth in claim 3 which is further characterized to include:

third normally open valve means interconnected in said first output fluid line and actuated to port fluid pressure simultaneous with actuation of said first and second valve means.

5. A control device as set forth in claim 3 wherein said means for sensing comprises:

means forsensing said amount of torque and providing a proportional hydraulic pressure output as said output indication.

6. A control device as set forth in claim 5 wherein said means responsive to said output indication comprises:

a hydraulic pressure actuated gauge having normally open electrical contacts which close at pre-set pressure to actuate said four-way valve. 

1. A control device for automated control of fluid pressure actuated master clutch and neutral brake which transmit primary power for operation of a well drilling rotary table, comprising: first valve means actuated to port fluid pressure from said brake to a first output fluid line; second valve means actuated to port fluid pressure from an input fluid line to said clutch; three-way valve means actuated to port fluid pressure from a fluid pressure source to a second output fluid line; and four-way valve means normally connecting said second output fluid line to said input fluid line to said second valve means while connecting said first output fluid line to a pressure exhaust line, said four-way valve means being actuatable to alternate porting connections whereby said input fluid line is connected to said pressure exhaust line to release the master clutch and said second output fluid is connected to said first output fluid line through said first valve means to actuate the neutral brake.
 2. A control device as set forth in claim 1 which is further characterized to include: third normally open valve means interconnected in said first output fluid line and actuated to port fluid pressure simultaneous with actuation of said first and second valve means.
 3. A control device as set forth in claim 1 which is further characterized to include: means for sensing the amount of torque applied to said rotary table and providing a proportional output indication; and means responsive to a pre-selected maximum of said output indication to actuate said four-way valve means.
 4. A control device as set forth in claim 3 which is further characterized to include: third normally open valve means interconnected in said first output fluid line and actuated to port fluid pressure simultaneous with actuation of said first and second valve means.
 5. A control device as set forth in claim 3 wherein said means for sensing comprises: means for sensing said amount of torque and providing a proportional hydraulic pressure output as said output indication.
 6. A control device as set forth in claim 5 wherein said means responsive to said output indication comprises: a hydraulic pressure actuated gauge having normally open electrical contacts which close at pre-set pressure to actuate said four-way valve. 